Day-to-day and within-day variation in urinary iodine excretion.

OBJECTIVE: To examine the day-to-day and within-day variation in urinary iodine excretion and the day-to-day variation in iodine intake. DESIGN: Collection of consecutive 24-h urine samples and casual urine samples over 24h. SETTING: The study population consisted of highly motivated subjects from our Institute. SUBJECTS: Study 1: Ten healthy subjects (seven females and three males) aged 30-46 y. Study 2: Twenty-two healthy subjects (9 males and 13 females) aged 30-55 y. METHODS: Study 1: 24-h urine samples were collected for four consecutive days. Study 2: Each urine voided over 24 h was collected into separate containers. In both studies dietary records were kept. MAIN OUTCOME MEASURES: Twenty-four-hour urinary iodine excretion, 24-h urinary iodine excretion estimated as I/Cr*24 h Cr and as a concentration in casual urine samples. RESULTS: Study 1: Both iodine excreted in 24-h urine and iodine intake varied from day-to-day. Iodine excretion correlated with iodine intake (=-0.46, P=0.01). Iodine intake (mean 89 +/- 6.5 microg/d) was not significantly different from iodine excretion (mean 95 +/- 5.3 microg/d). Study 2: Twenty-four hour iodine excretion estimated as I/Cr*24 h Cr from the morning urine sample was significantly lower than actual 24-h iodine excretion, whereas 24-h iodine excretion estimated as I/Cr*24 h Cr from the first sample after the morning sample and the last sample before the subjects went to bed was not significantly different from actual 24-h iodine excretion. Twenty-four-hour urine excretion estimated as a concentration was lower than actual 24-h iodine excretion in casual urine taken at any time of the day. CONCLUSIONS: For determination of iodine status in an individual, more than one 24-h urine sample must be used. The use of the I/Cr ratio in casual urine samples is a usable measure of iodine status if corrected for the age- and sex-adjusted 24-h creatinine excretion. Further, the study suggests that fasting morning urine samples would underestimate iodine status in this population.     

Ten repeat collections for urinary iodine from spot samples or 24-hour samples are needed to reliably estimate individual iodine status in women

Although the median urinary iodine concentration (UIC) is a good indicator of iodine status in populations, there is no established biomarker for individual iodine status. If the UIC were to be used to assess individuals, it is unclear how many repeat urine collections would be needed and if the collections should be spot samples or 24-h samples. In a prospective, longitudinal, 15-mo study, healthy Swiss women (n = 22) aged 52-77 y collected repeated 24-h urine samples (total n = 341) and corresponding fasting, second-void, morning spot urine samples (n = 177). From the UIC in spot samples, 24-h urinary iodine excretion (UIE) was extrapolated based on the age- and sex-adjusted iodine:creatinine ratio. Measured UIE in 24-h samples, estimated 24-h UIE, and UIC in spot samples were (geometric mean ± SD) 103 ± 28 μg/24 h, 86 ± 33 μg/24 h, and 68 ± 28 μg/L, respectively, with no seasonal differences. Intra-individual variation (mean CV) was comparable for measured UIE (32%) and estimated UIE (33%). The CV tended to be higher for the spot UIC (38%) than for the estimated 24-h UIE (33%) (P = 0.12). In this population, 10 spot urine samples or 24-h urine samples were needed to assess individual iodine status with 20% precision. Spot samples would likely be preferable because of their ease of collection. However, the large number of repeated urine samples needed to estimate individual iodine status is a major limitation and emphasizes the need for further investigation of more practical biomarkers of individual iodine status.     

Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values

OBJECTIVE: The most accurate way to measure urinary iodine excretion in epidemiological surveys is still debated. We propose a new principle of estimating iodine excretion based on casual urine samples. MATERIAL AND METHODS: A total of 123 24 h urine samples and corresponding casual urine samples were collected from 31 subjects. Iodine excretion was expressed as 24 h iodine excretion and three different estimates: iodine concentration in the casual sample, iodine/gram creatinine in the casual sample, and the new principle-iodine/creatinine ratio in the casual sample, adjusted for expected creatinine excretion of the individual. RESULTS: All three estimates based on casual urine samples correlated significantly to 24 h values with a r (Pearson) of 0.37 for iodine concentration, 0. 61 for iodine/creatinine ratio and 0.62 for the age- and sex-adjusted iodine/creatinine ratio. The median iodine excretion in the entire group was 143 microg/day in 24 h samples, 87 microg/l as iodine concentration, 77 microg/g creatinine as iodine/creatinine ratio and 126 microg/day as age- and sex-adjusted iodine/creatinine ratio. CONCLUSION: Age- and sex-adjusted iodine/creatinine ratio is a more accurate and unbiased estimate of iodine excretion in epidemiological surveys of adults than the two most frequently used estimated: iodine concentration and iodine/gram creatinine, as these two estimates may introduce a bias depending on the composition of the investigated group. The adjusted iodine/creatinine ratio is superior to the other estimates, especially when individual estimates of 24 h iodine excretion is required or cohorts of selected groups are investigated. Sponsorship: This work was supported by grants from the Medical Research Foundation Region Greater Copenhagen, Faroe Islands and Greenland; the Wedell-Wedellsborg Foundation; Musikforlaeggerne Agnes and Knut Morks Foundation.     

Urinary iodine and thyroid status of New Zealand residents

OBJECTIVES: The aim of this project was to assess the clinical significance of our low iodine excretions in terms of thyroid hormone status and thyroid volume in an adult population in a low soil iodine area of the South Island of New Zealand. DESIGN AND SETTING: Two-hundred and thirty-three residents of Otago, New Zealand collected two 24 h urine samples for assessment of iodine status. Thyroid status was determined from serum total T(4), TSH and thyroglobulin, and thyroid volumes. Relationships between urinary iodide excretion and measures of thyroid status were determined and subjects were allocated to one of three groups according to low, medium and high iodide excretion, for comparison of thyroid hormones and thyroid volumes. RESULTS: Significant correlations were found for relationships between measures of urinary iodide excretion and thyroid volume and thyroglobulin. Multiple regression analysis of data for subjects divided into three groups according to 24 h urinary iodide excretion (<60, 60-90; >90 microg iodide/day) or iodide/creatinine ratio (<40; 40-60; >60 microg/g Cr) showed significant differences in thyroid volume (P=0.029; P=0.035, respectively) and thyroglobulin (P=0.019; P=0.005, respectively) among the groups. CONCLUSIONS: The results of this study confirm the low iodide excretions of Otago residents, and indicate that the fall in iodine status is being reflected in clinical measures of thyroid status, including enlarged thyroid glands and elevated thyroglobulin. Our observations suggest the possible re-emergence of mild iodine deficiency and goitres in New Zealand. This situation is likely to worsen should iodine intakes continue to fall and continued monitoring of the situation is imperative.     

An evaluation of salt intake and iodine nutrition in a rural and urban area of the C?te d'Ivoire.

OBJECTIVE: To evaluate the habitual salt intake of individuals living in the C?te d'Ivoire, and to monitor the iodine nutrition of adults, schoolchildren and pregnant women one year after implementation of a universal salt iodisation programme. DESIGN: A three day weighed food records with estimation of food intake from a shared bowl based on changes on body weight, determination of sodium and iodine concentrations in 24 h (24 h) urine samples from adults, and determination of urinary iodine in spot urines from schoolchildren and pregnant women. SETTING: A large coastal city (Abidjan) and a cluster of inland villages in the northern savannah region of the C?te d'Ivoire. SUBJECTS: For the food records: 188 subjects (children and adults) in the northern villages; for the 24 h urine collections: 52 adults in Abidjan and 51 adults in the northern villages; for the spot urine collections: 110 children and 72 pregnant women in Abidjan and 104 children and 66 pregnant women in the north. MAIN RESULTS: From the food survey data in the north, the total mean salt intake (s.d.) of all age groups and the adults was estimated to be 5.7 g/d (+/- 3.0), and 6.8 g/d (+/- 3.2), respectively. In the 24 h urine samples from adults, the mean sodium excretion was 2.9 g/d (+/- 1.9) in the north and 3.0 g/d (+/- 1.3) in Abidjan, corresponding to an intake of 7.3-7.5 g/d of sodium chloride. In the north the median 24 h urinary iodine excretion in adults was 163 microg/d, and the median urinary iodine in spot urines from children and pregnant women was 263 microg/l and 133 microg/l, respectively. In contrast, in Abidjan the median 24 h urinary iodine was 442 microg/d, with 40% of the subjects excreting > 500 microg/d, and the median urinary iodine in spot urines from children and pregnant women was 488 microg/l and 364 microg/l, respectively. Nearly half of the children in Abidjan and 32% of the pregnant women were excreting > 500 microg/l. CONCLUSION: Based on the estimates of salt intake in this study, an optimal iodine level for salt (at the point of consumption) would be 30 ppm. Therefore the current goals for the iodised salt programme--30-50 ppm iodine appear to be appropriate. However, in adults, children and pregnant women from Abidjan, high urinary iodine levels--levels potentially associated with increased risk of iodine-induced hyperthyroidism--are common. These results suggest an urgent need for improved monitoring and surveillance of the current salt iodisation programme in the C?te d'Ivoire.     

血中铅,镉水平与其尿排泄关系的研究

报道了肌酐代谢无明显异常的17名职业性铅、镉接触者在自由饮水情况下血中铅、镉水平与其尿排泄的关系。结果表明,血中铅、镉浓度以及铅、镉、肌酐的尿排泄存在明显的个体差异。血铅浓度与24h尿铅排泄量呈明显正相关,血镉浓度与24h尿镉排泄量无明显相关,而与每天吸烟量明显相关。17人的132份尿样的尿流速与肌酐、镉排泄率呈显著正相关,但与尿铅排泄率无显著相关。本研究还表明,尿中肌酐排泄率与尿铅、镉排泄率之间也有显著的正相关性。     

Naturally occurring iodine in humic substances in drinking water in Denmark is bioavailable and determines population iodine intake

Iodine intake is important for thyroid function. Iodine content of natural waters is high in some areas and occurs bound in humic substances. Tap water is a major dietary source but bioavailability of organically bound iodine may be impaired. The objective was to assess if naturally occurring iodine bound in humic substances is bioavailable. Tap water was collected at Randers and Skagen waterworks and spot urine samples were collected from 430 long-term Randers and Skagen dwellers, who filled in a questionnaire. Tap water contained 2 microg/l elemental iodine in Randers and 140 microg/l iodine bound in humic substances in Skagen. Median (25; 75 percentile) urinary iodine excretion among Randers and Skagen dwellers not using iodine-containing supplements was 50 (37; 83) microg/24 h and 177 (137; 219) microg/24 h respectively (P < 0.001). The fraction of samples with iodine below 100 microg/24 h was 85.0 % in Randers and 6.5 % in Skagen (P < 0.001). Use of iodine-containing supplements increased urinary iodine by 60 microg/24 h (P < 0.001). This decreased the number of samples with iodine below 100 microg/24 h to 67.3 % and 5.0 % respectively, but increased the number of samples with iodine above 300 microg/24 h to 2.4 % and 16.1 %. Bioavailability of iodine in humic substances in Skagen tap water was about 85 %. Iodine in natural waters may be elemental or found in humic substances. The fraction available suggests an importance of drinking water supply for population iodine intake, although this may not be adequate to estimate population iodine intake.     

Anthropometry-based reference values for 24-h urinary creatinine excretion during growth and their use in endocrine and nutritional research

BACKGROUND: Urinary creatinine reference values that take anthropometric data into account, which is mandatory during growth, are not available for healthy white children. OBJECTIVE: We sought to establish anthropometry-based reference values for 24-h urinary creatinine excretion in healthy white children aged 3-18 y. DESIGN: Anthropometric variables and 24-h urinary creatinine excretion rates were determined cross-sectionally (225 boys and 229 girls). Age and sex dependency of 24-h creatinine excretion (crude and related to individual anthropometric variables) were assessed to derive appropriate creatinine reference values. The applicability of these creatinine reference values for estimation of daily excretion of certain analytes was assessed in 40 additional children. RESULTS: Sex-specific, body-weight-related creatinine reference values were derived for the following age groups: 3, 4-5, 6-8, 9-13, and 14-18 y. The 5th percentile exceeded 0.1 mmol x kg(-1) x d(-1) in all age groups >3 y. The use of these creatinine reference values for estimating average 24-h excretion rates of certain analytes (determined as the ratio of analyte to creatinine in spot urine samples) yielded reasonable estimates of mean 24-h urinary excretion rates actually analyzed (spot and 24-h urine samples from the same children). Ideal 24-h creatinine excretion values for height were also derived for a potential determination of the creatinine height index. CONCLUSIONS: Established anthropometry-based creatinine reference values are recommended as a convenient, simple tool to 1) identify severe 24-h urine collection errors, 2) calculate average 24-h excretion rates of certain analytes (from respective ratios of analyte to creatinine) determined in spot urine samples, and 3) assess somatic protein status by determining the creatinine height index.     

Quantification of urinary iodine: a need for revised thresholds

OBJECTIVE: To compare different possibilities of reporting the iodine supply in the same urine samples. Indeed, in field studies, urinary iodine concentration (I/L: micro g I/L, micro mol I/L, I/creatinine: micro g I/g creatanine, micro mol I/mol creatinine) is more readily available than excretion (I/24h micro g I/24 h, micro mol I/24h). However, confusion exists regarding the comparability of iodine supply based upon I/L, I/creatinine and I/24h, which for decades have been regarded as biochemically equivalent. DESIGN: We compared I/24h, I/L and I/creatinine in accurate 24 h collections of urine and I/L and I/creatinine in 47 spot urine samples. PATIENTS: A total of 13 subjects (Bern n=7, Brussels n=6) collected a total of 110 precise 24 h urine collections (Bern n=63, Brussels n=47). The subjects from Brussels also took a spot sample at the beginning of each 24 h collection. RESULTS: Iodine supply in both places was mildly deficient according to the criteria of WHO; all but one collection indicated an intake of >0.39 micro mol I/24h (>50 micro g I/24h). The same data presented as I/creatinine (or I/L) indicated an iodine intake of <0.39 (<50 micro g I/24h) in 5% (24%) of the samples in Bern and 23% (57%) in Brussels. Similar findings were observed for 47 spot samples. Whatever the cut-off selected, I/creatinine and I/L were systematically lower than I/24h (P<0.0002). Creatinine showed smaller CV than volume but did not perform better in defining iodine intake. CONCLUSION: Considering I/24h as a reference, both I/creatinine and I/L clearly underestimate the iodine intake in subjects with adequate proteoenergetic intake. The significant deviations observed illustrate the urgent need for establishing separate ranges for I/24h, I/creatinine and I/L. In population studies, these deviations might even be larger.     

Changes in iodine excretion in 50-69-y-old denizens of an Arctic society in transition and iodine excretion as a biomarker of the frequency of consumption of traditional Inuit foods

BACKGROUND: Iodine intake in Greenland has been hypothesized to exceed 10 times the recommended amount. The transition from a traditional Arctic society may change the iodine intake, but no field studies have been performed. OBJECTIVE: We aimed to ascertain iodine intakes, factors affecting iodine intake in circumpolar populations, and the usefulness of urinary iodine excretion as a biomarker for validation of Inuit food-frequency questionnaires. DESIGN: Data were collected in a cohort study of 4 Greenland population groups: Inuit living in the capital city, the major town, and settlements in East Greenland and non-Inuit. Supplement use and lifestyle factors were evaluated with questionnaires, and dietary habits were ascertained with a food-frequency questionnaire. Iodine was measured in spot urine samples. RESULTS: One percent of the population of Greenland was invited, and the participation rate was 95%. Less than 5% of Inuit but 55% of non-Inuit had urinary iodine excretion < 50 microg/24 h. Median urinary iodine excretion declined with the degree of decrease in the traditional lifestyle: it was 198, 195, 147, and 58 microg/24 h among Inuit in settlements, town, and city and in non-Inuit, respectively (P < 0.001). Participants were divided into diet groups calculated from Inuit food frequency. Iodine excretion decreased with increasing intake of imported foods (P < 0.001). In regression models, type of diet and the subject's lifestyle, sex, weight, ethnicity, and intake of iodine-containing supplements affected urinary iodine excretion. CONCLUSIONS: Circumpolar non-Inuit are at risk of iodine deficiency. Departure from the traditional Inuit diet lowers iodine intake, which should be monitored in Arctic societies. Urinary iodine excretion may be a useful biomarker of traditional Inuit food frequency.     

尿中肌酐排泄稳定性的研究

分析在自由饮水条件下７７３个健康人的一次点尿样，６２人的２４ｈ尿样及８人连续５天收集的２４ｈ尿样，对这些尿样分别测定比重、肌酐浓度及肌酐排泄量，以揭示尿肌酐排泄的稳定性。研究发现，尿肌酐浓度与尿比重之间具有一定的相关性，尿肌酐排泄存在明显的个性差异和体内变异。可以认为，肌酐排泄的稳定性较差，用肌酐作为尿毒物浓度的校正参数，其适合性和可靠性值得怀疑。     

碘摄入量与晨尿中碘排量的关系研究

目的研究晨尿的尿碘含量及其肌酐校正的每日尿排碘量与碘摄入量的相关关系,探讨准确反映机体碘摄入量的指标。方法将经筛选的161名志愿者随机分为500～2000μg/d的7个剂量组中。采用7d膳食记录法计算膳食碘摄入量。在给与碘补充剂后第0、2、4w取空腹晨尿,分别以砷铈催化分光光度法和碱性苦味酸法测定尿碘含量和尿肌酐含量,并计算出肌酐校正的每日尿排碘量。对各组晨尿碘含量和每日尿排碘量进行方差分析,并与碘摄入量进行回归分析。结果膳食中碘的摄入量在各剂量组间没有显著性差异,均值为328μg/d。给碘补充剂前晨尿碘含量和肌酐校正的每日尿排碘量在各剂量组间均没有显著性差异(P>0.05),均值分别为325μg/L和314μg/d。而给碘补充剂后第2、4w晨尿碘含量和肌酐校正的每日尿排碘量随剂量的增加而增加,在各剂量组间均有显著性差异(P<0.05)。回归分析显示其相关系数在0.958～0.976之间(P=0.000),肌酐校正的每日尿排碘量与碘摄入量回归方程的斜率接近1。结论晨尿的尿碘含量及肌酐校正的每日尿排碘量都是表述机体碘摄入量的敏感指标。因晨尿尿碘含量易受干扰而波动,只适用于大样本群体的碘营养状况调查。晨尿经肌酐校正的每日尿排碘量相对比较稳定,能更准确地反映碘的摄入量,既适用于群体,也适用于个体的碘营养状况评价。     

人群两次24小时尿量及食盐摄入量关联性分析

  目的   分析两次24 h尿量和尿盐排出量, 探讨24 h尿用于评估群体和个体食盐摄入量的价值。   方法   于2013-2014年在山东省和江苏省4个项目县, 采用多阶段整群随机抽样的方法, 抽取18~69岁调查对象进行问卷调查并收集间隔1 d两次24 h尿液, 比较两次24 h尿量的差异, 从个体和群体两个层面分析两次24 h尿盐排出量的差异。   结果   1 288名研究对象年龄为(42.3±14.0)岁, 男性626名(48.6%)。24 h平均尿量为(1 462±437)ml, 第1次24 h尿量(1 427±488)ml低于第2次24 h尿量(1 498±552)ml(t=-4.439, P < 0.001)。调查对象每日食盐摄入量为(9.8±3.3)g, 男性每日食盐摄入量(10.1±3.5)g高于女性(9.5±3.1)g(t=3.09, P=0.002), 不同年龄组人群每日食盐摄入量差异有统计学意义(F=7.57, P < 0.001), 1 136名(88.2%)研究对象每日食盐摄入量高于推荐值。从个体层面比较, 调查对象两次24 h尿盐排出量绝对差异 < 1 g, 人数为279(21.7%), 而有48.5%的调查对象差异 > 3 g。从群体层面比较, 调查对象两次24 h尿盐排出量分别为(9.9±4.1)g和(9.7±4.0)g, 差异无统计学意义(P=0.102), 两次24 h尿盐排出量的组内相关系数为0.508(95% CI:0.451~0.559)。   结论   本研究结果提示24 h尿钠能较好评估人群食盐摄入量, 但不能准确反映个体食盐摄入量。     

Assessment of iodine deficiency in Kottayam district, Kerala State: a pilot study

Iodine is one of the essential micro-elements required for normal human growth and development. Iodine Deficiency Disorders (IDD) are an important public health problem in India. There has been no data on the prevalence of IDD from the Kottayam district, India and hence, the present pilot study was conducted in the year 1999 to assess whether iodine deficiency existed in the district or not and to estimate the iodine content of salt consumed by the population. A total of 1872 children in the age group of 6-12 years were included in the study and were clinically examined. On the spot urine samples were collected from 251 children. A total of 420 salt samples were collected randomly from the families of the children. The total goitre prevalence was found to be 7.05% in the subjects studied. It was found that the percentage of children with urinary iodine excretions of < 2, 2- < 5, 5-9 and 10 microg/dL and above were 6.4%, 6.0%, 20.7%, and 66.9%, respectively. Assessment of the iodine content of salt by the iodometric titration method revealed that 60.6% of the children were consuming salt with an iodine content of 15 p.p.m. and more, which was the stipulated level of salt iodisation. The findings of the present study indicated that the population is in a transitional phase from iodine deficient, as revealed by total goitre rate, to iodine sufficient nutriture, as revealed by the median urinary iodine excretion level of 17.5 microg/dL.     

A normative value pilot study: levels of uranium in urine samples from UK civilians

A normative study of the levels of urinary uranium in the general UK population is needed for comparison with levels in UK military and ex-military personnel who served where munitions containing depleted uranium (DU) were used. As preparation, this pilot study trialled the process of collecting 24-h samples from adult male civilians, and compared the measurements from 24-h samples with those from spot samples taken over the subsequent 24h. The purpose was to assess the relative utility of the two types of samples. Twenty-five convalescent hospital in-patients were recruited as participants. Uranium concentrations in the 24-h samples ranged from 1 to 10.6 ng l(-1); in the spots, from not detectable to 38.1 ng l(-1). Normalised to creatinine, concentrations in the 24h samples ranged from approximately 100 to 800 ng mol(-1) creatinine; in the spot samples, from not detectable to approximately 4000 ng mol(-1) creatinine. The ranges appear similar to those reported for residents of the US. The distribution of spot sample results indicated that 95% of a participant's creatinine-adjusted concentrations from spot samples would be within the range 40-250% of his mean. Adjusting for creatinine almost entirely eliminated a slight indication of diurnal variation in urinary uranium concentration in spot samples. All the 24-h samples and 131 out of the 133 spot samples showed ratios of isotopes (238)U to (235)U consistent with natural uranium (i.e. neither enriched nor depleted). Slightly elevated ratios in two spot samples were not supported by other samples from the same participants, indicating that slightly elevated ratios may be recorded on very low concentration (<1 ng l(-1)) samples. In the main, quantification of this isotope ratio from spot samples was only slightly more variable than from 24-h samples. Complete 24-h urine samples gave better precision than spot samples in estimating uranium concentrations at these low levels, but presented more logistic difficulties in the collection of the samples. Clarification of the relative merits of alternative sampling strategies enables the design of a wider study to be optimised.     

Formulas developed based on the ratio of urea nitrogen to creatinine concentrations obtained from multiple spot urine samples are acceptable to predict protein intake at group level but not at individual level

In this study, we hypothesized that spot urine can be used to predict protein intake at both group and individual levels. Participants (n = 369) of this study were recruited from all 47 prefectures in Japan. Sex-specific formulas were developed based on the ratio of urea nitrogen to creatinine concentration obtained from 3 spot urine samples. Validity of the formulas was examined against two 24-hour urine collections for 7 combinations of spot urine (single and means of 2 or 3 samples) using t test (mean estimation), Spearman correlation, and Bland-Altman plot (individual bias). Means of measured protein intake based on 24-hour urinary excretions were 87.3 g/d (standard deviation 19.7) for men and 70.5 g/d (standard deviation 14.7) for women. Irrespective of sex, the predicted intakes were not significantly different (within 2.7% of differences) from those measured by urinary excretions. Predicted intakes were moderately correlated with measured intakes (men, 0.45-0.60; women, 0.35-0.53). Even after using the mean of 3 samples, Bland-Altman plots showed a considerably wide limit of agreement (men, −30 to 33 g/d; women, −27 to 24 g/d). Except for using single spot urine samples in women, the formula tended to overestimate intake at a lower and underestimate at a higher level of protein intake (slope: men, −0.47 [P < .0001]; women, −0.38 [P = .002]). In conclusion, predictive formulas developed in this study can be used to predict protein intake at group level or to rank individuals' intake but not to predict absolute intake at individual level.     

Effect of tamarind ingestion on fluoride excretion in humans

OBJECTIVE: To evaluate the effect of tamarind (Tamarindus indicus) ingestion on excretion of fluoride in school children. DESIGN: Randomized, diet-control study. SUBJECT: Twenty healthy boys were included and 18 of them completed the study. INTERVENTIONS: Each subject consumed 10 g tamarind daily with lunch for 18 days at the social welfare boys' hostel. The nutrient composition of the daily diet was constant throughout the experimental period. RESULTS: Tamarind intake led to significant increase (P<0.001) in the excretion of fluoride in 24 h urine (4.8+/-0.22 mg/day) as compared to excretion on control diet (3.5+/-0.22 mg/day). However, excretion of magnesium and zinc decreased significantly (7.11+/-1.48 mg of Mg and 252.88+/-12.84 microg of Zn per day on tamarind diet as compared to 23.39+/-3.68 mg of Mg and 331.78+/-35.31 microg Zn per day on control diet). Excretion of calcium and phosphorous were not significantly different while creatinine excretion decreased with tamarind intake (225.66+/-81 mg creatinine/day with tamarind and 294.5+/-78.76 mg creatinine/day without tamarind). CONCLUSION: Tamarind intake is likely to help in delaying progression of fluorosis by enhancing urinary excretion of fluoride.     

Iodine intake before and after mandatory iodization in Denmark: results from the Danish Investigation of Iodine Intake and Thyroid Diseases (DanThyr) study

Iodine deficiency is still common in some European countries. In Denmark an iodine fortification programme was introduced in 1998 and a monitoring programme was established prior to iodization. This study reports the change in urinary iodine excretion caused by fortification and investigates determinants of iodine intake after fortification. Iodine excretion in casual urine samples was assessed in 4649 subjects in 1997-8 and in 3570 comparable subjects in 2004-5 in women 18-22, 25-30, 40-45 and 60-65 years of age and in men 60-65 years of age living in Aalborg (western part of Denmark) or Copenhagen (eastern part of Denmark). These areas had moderate and mild iodine deficiency, respectively, before iodine fortification. All subjects filled in a FFQ and a questionnaire regarding lifestyle factors. Iodine excretion, expressed as the estimated 24 h urinary iodine excretion and as urinary iodine concentration, increased significantly in all age and sex groups. However, the iodine intake was still below the recommended in the youngest age groups in both cities and in women 40-45 years of age living in Aalborg. Intake of milk and salt had strong significant direct associations with iodine excretion (P < 0.001). It is concluded that although the median iodine intake in the whole study population is at the recommended level, some groups still have an intake below the recommended. It is important to have a moderate milk intake to obtain a sufficient iodine intake in Denmark.     

Persistence of iodine deficiency in Gangetic flood-prone area, West Bengal, India

In 2000, India revoked the ban on production and sale of non-iodised salt. We conducted a study in the north 24 Parganas district in the state of West Bengal to assess the prevalence of goitre, status of urinary iodine excretion (UIE) level and to estimate iodine content of salts at the household level. We surveyed 363 school children aged eight to ten years selected using a multistage cluster sampling technique. We estimated goitre prevalence and urinary iodine excretion (UIE) using methods and criteria recommended by the World Health Organization. We estimated the iodine content of salt samples collected from the households of the study subjects using spot iodine testing kit. Of the 363 children, 73 (20%) had goitre. The median UIE was 160 micro g/l (normal: > or =100 micro g/l) and only 6% children had a level below 50 micro g/l. Only 253 of 363 salt samples (70%) were sufficiently iodised. The combination of high goitre prevalence with normal median urinary excretion indicates that the North 24 Parganas district is in transition from iodine deficient to iodine sufficient state. However, the persistence of non-iodised salt consumption indicates that an intensification of universal salt iodisation program is needed. In 2000, India revoked the ban on production and sale of non-iodised salt. We conducted a study in the north 24 Parganas district in the state of West Bengal to assess the prevalence of goitre, status of urinary iodine excretion (UIE) level and to estimate iodine content of salts at the household level. We surveyed 363 school children aged eight to ten years selected using a multistage cluster sampling technique. We estimated goitre prevalence and urinary iodine excretion (UIE) using methods and criteria recommended by the World Health Organization. We estimated the iodine content of salt samples collected from the households of the study subjects using spot iodine testing kit. Of the 363 children, 73 (20%) had goitre. The median UIE was 160 micro g/l (normal: > or =100 micro g/l) and only 6% children had a level below 50 micro g/l. Only 253 of 363 salt samples (70%) were sufficiently iodised. The combination of high goitre prevalence with normal median urinary excretion indicates that the North 24 Parganas district is in transition from iodine deficient to iodine sufficient state. However, the persistence of non-iodised salt consumption indicates that an intensification of universal salt iodisation program is needed.     

Patients with severe bowel malabsorption do not have changes in iodine status

OBJECTIVE: We evaluated the influence of intestinal malabsorption on iodine status in patients who had short gut syndrome and received total parenteral nutrition (group I) compared with control subjects who had eutrophia (group II) and patients who had other illnesses but normal digestive tracts (group III). METHODS: Twenty-seven subjects were studied. Iodine intake was determined by the measurement of iodine in ingested food and in parenteral nutrition solutions. Urinary iodine excretion was measured by the Sandell-Kalthoff reaction. Urinary creatinine, anthropometric, and thyroid hormone functions were also determined. RESULTS: Daily iodine intakes were 658 +/- 125 (mean +/- standard deviation), 573 +/- 204, and 629 +/- 208 microg for groups I, II, and III, respectively. Daily urinary iodine excretion levels were 399 +/- 308, 439 +/- 192, and 370 +/- 268 microg and ratios of urinary iodine (micrograms) to creatinine (grams) were 614 +/- 349, 354 +/- 142, and 483 +/- 292, respectively. There were no statistically significant differences across groups. CONCLUSION: In Brazil the iodine provided by food, including iodized salt, has been sufficient to maintain iodine status in patients with short gut syndrome.